The present invention relates to a bearing for use with an electrical machine that includes a drive shaft mounted in a housing.
European Published Patent Application No. 698 956 describes a known bearing in which a spherical cap, which is made of sintered material and with which a repository for lubricant is associated in order to lubricate the bearing, is used to mount a driving shaft of an electrical machine. Located between the spherical cap and the commutator is a thrust washer or cover disk which consists of a first solid annular disk element and a second elastic disk element joined positively thereto. The solid disk element has two peripheral slinger edges facing the spherical cap. The sintered material used for the spherical cap has the property that because of the capillary effect of the interstices which are present, lubricant is stored and is delivered to the drive shaft during operation as a result of pressure differences. This results in lubrication of the driving shaft, so that it is mounted in a low-friction and low-wear manner in the spherical cap. Due to heating of the sintered bearing during operation of the electrical machine, however, an increase in the volume of the stored lubricant can occur, so that it can emerge laterally out of the sintered bearing. This lubricant emerging during operation is thrown onto the bearing housing via the slinger edges, and returns from there to the spherical cap. This arrangement allows reliable sealing of the bearing even with large assembly tolerances. The two-part configuration of the slinger disk nevertheless requires increased manufacturing and assembly outlay. Moreover, without additional sealing measures it is impossible to rule out completely the possibility that lubricant slung onto the housing wall may penetrate via the surrounding housing to the adjacent commutator.
U.S. Pat. No. 4,711,590 discloses a bearing device for mounting the driving shaft of an electrical machine, having a one-piece slinger disk made of a solid material. The bearing arrangement as a whole is separated by means of a housing from rotating parts arranged on the driving shaft.